This invention relates to a screw-rotor machine with two screw rotors and more particularly to the profile of the intermeshing rotors for such kind of machine.
As everybody knows, the rotors in screw-rotor machines are provided with helical lands and intervening grooves and are adapted for rotation around parallel axes in a working space in the machine. One of the rotors is named female rotor and so designed that a major portion of each groove is located inside the pitch circle of the female rotor, and a minor portion of each groove is located outside the pitch circle. The second rotor is named male rotor and so designed that a major portion of each land is located outside the pitch circle of the male rotor, and a minor portion of each land is located inside this pitch circle.
Heretofore, a plurality of patents relating to different inventions of rotor profiles for screw-rotor machine have been granted. The prior arts were replete with rotor profiles for machines of the type noted herein, and had brought forth improvement in the performance of the machine. Examplary thereof are U.S. Pat. Nos. 4,028,026, 4,140,445, 4,412,796, 4,435,139 and 4,460,322. But, according to the prior arts, in order to have the rotor profiles with an optimum relation between these two rotors as regards the adiabatic efficiency, the profiles are difficult to designate and complicated to manufacture.
It is an object of this invention to achieve a rotor profile, which meets this optimum relation in order to bring about a screw-rotor machine having an adiabatic efficiency exceeding that has been obtained with heretofore known profiles.
It is further object of this invention to achieve the rotor profiles by a more simplified procedure, that is, to provide a simple process to get the rotor profiles.